Internet keeps going to limited connection every few seconds?

[anomynous]

I have a wireless linksys router and every few seconds my internet goes limited connection and then a couple seconds later it sorts itself out without me having to do anything which is extremely irritating. I have tried the likes of changing wireless channels but it isn't helping. What else can I try to sort this out?
Phone line is fine

[Neil]

Have you tried disconnecting the filter from phone socket or if you're using 2 filters, swap them over. Is your phoneline crackling?

[polar vortex]

Reset the router and see if it makes any difference. Here's a how-to link.

[Boss]

Replace router.